Magazine closure and guide assembly for stapling implements



Sept. 13, 1966 HOW D ETAL 3,272,417

SSEMBLY FOR MAGAZINE CLOSURE A GUIDE A STAPLING MENTS Filed Fe 1965 INVENTORS: FRANK HOWARD ARTHUR LANGAS United States Patent 3,272,417 MAGAZINE CLDSURE AND GUEDE ASSEMBLY FOR STAPLKNG EMPLEMENTS Frank Howard, Wheeling, and Arthur Langas, Chicago,

Ill., assignors to Signode Corporation, a corporation of Delaware Filed Feb. 17, 1965, Ser. No. 433,337 9 Claims. (Cl. 227-123) The present invention relates to improvements in stapling implements and has particular reference to a novel jam proof magazine closure and staple guide assembly for such implements.

The jamming of staples in the throat or guidcway which invariably is provided at the forward end of the supply magazine of a stapling implement has long presented a problem. The causes of such jamming are varied and, principal among them is the occasional faillure of the leading staple of a given refill cartridge to completely clear the shear block and move wholly into the confines of the throat or guideway. In such an instance, when the driver descends upon the staple, it engages only the overhanging portion of the staple crown and the staple, instead of being properly sheared from the next adjacent staple in the cartridge, is ripped therefrom and the crown portion is canted out of its normally horizontal plane so that it assumes a vertical position within the throat or guideway. The staple driver may then pass alongside the staple, thus creating a jam in the upper regions of the guideway. Another frequent cause of jamming is the inability of a given staple to penetrate or pierce the work, as for example when a hard spot is encountered. in such an instance the jam usually occurs in the lower region of the guideway; Other causes of jamming, as for example, the existence of a defective staple, may result in clogging of the guideway at any region therealong.

Heretofore, efforts to alleviate the annoyance attendant upon the jamming of staples have been directed principally to the provision of removable closure members at the forward end of the staple magazines and which, when a jam occurs, may conveniently be removed to expose the guideways or throats for withdrawal of the misaligned or distorted staples. A closure member of this general type usually constitutes the front wall of the throat so that when it is removed, the throat is exposed for forward removal of the jammed staple or staples. Various means are provided for facilitating removal of such closure members without necessitating the removal of fastening screws or other fastening devices, some such members being slidable into and out of position and being held in position by releasable detent means. Other closure members are swingable into and out of position in the manner of a gate, and being similarly locked in position by detent devices.

:Removable closure members of the type briefly outlined above are effective to correct a condition of staple jam only when considerable manipulation thereof is resorted to. Even though removal of the closure plate along may relieve the jammed condition by allowing the jammed staple or staples to fall freely from the throat, replacement of the closure plate is troublesome and requires attention, as well as undue handling of the tool during closure plate alignment when it is being replaced. Such removable closure members make no provision for preventing a jam in the first place.

The present invention is designed as an improvement over end closure assemblies of the above-described character and which are merely of a corrective nature in that they facilitate remedial measures after a jam has actually taken place. Accordingly, it is among the principal and general objects of the invention to provide a novel magazine closure and staple guide assembly which, in addition to employing a readily removable closure member or front wall for the staple guideway or throat, further provides a yielding support for such closure memher so that when, for any reason whatsoever, a given staple becomes deformed in the throat the closure member will yield laterally so that there will be no binding of the staple and the latter will then automatically be ejected from the throat under the influence of the driver, either during the initial stroke thereof or, at least, during the next succeeding stroke when a following staple, acting in an intermediate capacity, will effect the actual ejection of the deformed staple.

Briefly, in carrying out the above mentioned object, the invention contemplates the provision of a unitary package-type of assembly including three principal parts, namely a combined shear block and guide member; a front closure plate which, in combination with the first part, establishes a staple guideway or throat; and a spring retainer for maintaining the front closure plate in position on the combined shear block and guide member. The entire assembly is removably held in position at the front open end of the magazine by fastening screws. The closure plate, which constitutes the front wall for the throat, is slidable edgewise into and out of operative position on the guide member and cooperating releasable detent latch means on the retainer and plate maintain the latter in position on the guide member. The cooperating detent means on the retainer and closure member includes a series of spring fingers on the retainer and cooperating detent recesses in the closure member. The spring fingers on the retainer, in addition to their detent function, also serve to yieldingly hold the closure plate in position while allowing the same to yield laterally so that in the event that a given staple becomes deformed the pressure exerted thereby upon the closure plate will force the latter away from the guide member and, in effect, widen the throat so that the defective staple will not bind in the throat. in most instances the driver will then automatically eject the offending staple during the initial stroke which occasioned the staple deformation but, if for any reason the driver moves past the staple, the next succeeding stroke of the driver will cause ejection of the staple through the media of a succeeding staple which is sheared from the cartridge of staples and caused to eject the deformed staple. After a given deformed staple has thus been ejected from the throat, the spring fingers will cause the closure plate to return to its normal position without attention on the part of the operator, thus restoring the assembly to its normal or initial condition. The detent means whereby the closure member is held in its latched position on the guide member is not affected by lateral movement of the closure member and the same remains in its latching condition at all times except when the latching effect thereof is overcome by manual force during removal of the closure member. Such removal of the closure member from the assembly is resorted to only when an abnormal deformation of staples within the throat takes place.

The provision of a jam-proof magazine closure and staple guide assembly of the character briefly outlined above constituting the principal object of the invention, a further object is to provide a yieldable closure mem her which, although of rigid construction, will yield bodily to the pressure exerted by a deformed staple, whether the pressure be exerted therea-gainst at the upper end of the throat, at the lower end thereof, or at any intermediate throat region. Thus, if a particular staple deformation causes lateral pressure to be exerted upon the closure plate in the upper region of the throat, the upper end of the closure plate will yield to accommodate the deformation. Then, as the driver forces the deformed staple downwardly, the closure plate will rock, so to speak, upon the staple as the latter is displaced by the driver, the medial region of the closure plate shifting laterally to allow the deformed staple to pass, and the lower end of the closure plate finally shifting to allow the deformed staple to leave the throat.

'It is a still further object of the invention, in a magazine closure and staple guide assembly of the type under consideration, to provide novel means whereby manual removal of the closure member, when desired, is facilitated, such means assuming the form of a prying lug on the closure member and which, when the latter is in position on the guide member, is so disposed with respect to one or more of the fastening screws by means of which the assembly is held in place, that it may be engaged by one end of a screwdriver or other similar tool, and (forced downwardly under the prying influence of the tool, utilizing the head of the fastening as a reaction point for effecting the prying operation.

The provision of a magazine closure and staple guide assembly which is comprised of a minimum number of parts and which therefore may be manufactured at a low cost; one which has few movable parts and which therefore is unlikely to get out of order; one which is rugged and durable and which therefore will withstand rough usage; one which is capable of ease of assembly and installation, and of disassembly for purposes of inspection of parts or replacement thereof; and one which, othenwise, is well adapted to perform the services required of it, are further desirable features which have been borne in mind in the production and development of the present invention.

Other objects and advantages of the invention, not at this time enumerated, will readily suggest themselves as the following description ensues.

In the accompanying single sheet of drawings forming a part of this specification, one illustrative embodiment of the invention has been shown.

In these drawings:

FIG. 1 is a perspective view of a stapling implement showing the improved magazine closure and guide assembly operatively installed thereon;

FIG. 2 is an enlarged fragmentary sectional view taken substantially centrally and longitudinally through the magazine closure and guide assembly and an adjacent portion of the staple magazine, the parts being shown in their normal positions;

FIG. 3 is an enlarged front elevational view of the assembly, showing the same detached from the tool body;

FIG. 4 is a sectional view taken substantially along the line 44 of FIG. 3;

FIG. 5 is a front elevational view of a combined shear block and guide member employed in connection with the invention;

FIG. 6 is an exploded perspective view of the assembly and illustrating its positional relationship with respect to the tool body; and

FIG. 7 is a sectional view similar to FIG. 2, the parts being shown in the positions which they assume under the influence of a deformed staple, and also illustrating the manner in which the deformed staple is ejected from the staple guideway.

Referring now to the drawings in detail and in particular to FIG. 1, a combined magazine closure and guide assembly embodying the principles of the present invention has been designated in its entirety at v10 and it is shown as being operatively installed upon a stapling implement 12. The implement 12 may be of any suit able type and, for illustrative purposes herein, it is shown as being in the form of a pneumatically operated tacker of the type shown and described in a copending United States application of Harrison C. Lingle, Serial No. 391,604 and entitled, Magnetic Magazine.

Briefly, the stapling implement 12 involves in its gen eral organization a main body portion 14, a handle portion 16, a magazine assembly 18, and a nose portion (see also FIG. 2). The implement 12 is adapted to be connected by a swivel fitting 22 to a source of air under pressure and the admission of such air into the body of the implement is controlled by a valve mechanism (not shown) actuated by a trigger assembly 26. The handle portion 16 terminates in a foot portion 28 and the magazine 18 extends between such foot portion and the nose portion 20 in underlying relationship with respect to the handle portion 16.

The magazine assembly 18 selected for illustration herein is of the magnetic type wherein a magnetic bar 30 (FIGS. 2 and 7) holds the staple cartridge 32 in position within the magazine chamber 34, such a magazine assembly constituting the subject matter of the above mentioned copending application, Serial No. 391,604. Only such portions of the magazine assembly 18 as are necessary for an understanding of the present invention have been illustrated herein and for a vfull understanding of the nature and operation of the magazine assembly 18 reference may be had to such copending application. For purposes of description herein it is deemed suflicient to state, briefly, that the assembly 18 includes an inverted channel-shaped member 35 of non-magnetic material, such member defining the aforementioned magazine chamber 34. The magnetic bar 30 overlies and rests upon the member 35 so that the crown portions 36 of the individual staples S which cooperate to make up the staple cartridge 32 are attracted to and held in sliding contact with the channel web 38. The lower portion of the channel member 35 is open for easy introduction of the staple cartridge 32 into the magazine chamber 34. A pole plate 40 overlies the magnetic bar 30 and serves as a protective shield therefor. The magazine 18 is provided with the usual slidable follower assembly 42 which is connected to one end of a spring 44, the other end of the spring being suitably secured to the nose portion 20.

The tool body 14 is provided with an internal cylinder (FIGS. 2 and 7) within which there is disposed a piston (not shown), the latter being operatively connected to a driver 52 which projects downwardly through a slot 54 in the tool body for driving cooperation with the staples S as they issue from the magazine 18 in the usual manner of driver operation, and for cooperation with the magazine closure and guide assembly 10 in a manner that will be described presently.

The arrangement of parts thus far described is purely conventional and no claim is made herein to any novelty associated with the same, the present invention residing rather in the novel construction, combination and arrangement of parts associated with the magazine closure and guide assembly 10 and which will now be described in detail and subsequently claimed.

As best seen in FIGS. 1 and 2, the nose portion 20 exists by reason of an angular recess formed in the tool body 14 and this recess is designed for reception therein of the assembly 10. The assembly 10 involves in its general organization three principal parts including a combined shear block and guide member 62, a closure plate 64 and a spring retainer 66.

The combined shear block and guide member 62 is in the form of a machined casting including a relatively thick vertically disposed plate portion and a shear block proper 72 which projects rearwardly from the plate portion '70. The plate portion 70 constitutes a staple guide plate and, accordingly, it is formed with a vertical slot or channel 74 therein (FIGS. 4 and 5) which, in combination with the closure plate 64, establishes a vertical throat 76 for downward movement of the staples S under the influence of the driver 52, the throat also constituting a raceway for the driver 52. The shear block 72 projects centrally and rearwardly from the rear side of the guide plate '70, the side edge regions of the plate projecting outwardly beyond the sides of the shear block and being formed with holes 78 therein designed for reception of fastening screws 80 by means of which the assembly as a whole is secured to the nose portion of the tool body 14. The fastening screws 80 pass through bores 82 formed in the nose portion 20 (FIG. 6) and cooperate with nuts 84 which seat within recesses 86 in the nose portion.

When the assembly 10 is in position on the nose portion 20, the shear block 72 projects through a slot 88 (FIG. 6) in the nose portion 20 and is aligned with the longitudinal axis of the magazine chamber 3 4 and with the staple cartridge 32. Sufficient clearance is provided between the outer sides of the shear block 72 and the side walls of the slot 88 that the staples S may pass forwardly through the nose portion 20 in straddling relation with respect to the shear block and enter the throat 76 through an inverted U-shaped passage 90 (FIGS. 5 and 6) for subsequent engagement by the driver 52. The channel 74 registers with the passage 90 so that the staples which pass forwardly from the magazine through the passage will immediately be projected into the throat 76 and against the opposed inner side of the closure plate 64. The slot 88, in effect, constitutes a continuation of the magazine chamber 34.

As best seen in FIGS. 5 and 6, the side walls of the slot 74 are recessed to provide a pair of opposed guideways 92 for sliding reception therein of the side edges of the closure plate 64. This latter member is in the form of a machined plate of generally rectangular design and of appreciable thickness. The extreme lower edge of the closure plate is bevelled as at 94 while the upper edge region thereof is of reduced thickness as indicated at 96 (see also FIG. 7). A slight distance above the bevelled area 94, the member 64 is formed with a pair of detent recesses 98 and a slight distance below the reduced region 96, a similar pair of detent recesses 100 are provided (see also FIG. 3). The upper recesses 100 merge with the reduced region 96 along a bevelled area 102. Similar bevelled areas 104 are formed at the both the upper and the lower edges of the recesses 98, the various bevelled areas serving a function that will be made clear presently.

The spring retainer 66 is provided for the purpose of yieldably maintaining the closure plate 64 in position on the guide plate 62 with the side edges of the plate being confined in the opposed guideways 92 as clearly shown in FIG. 4. Accordingly, the retainer 66 is in the form of a flat, relatively thin spring steel stamping, the marginal contour of which is approximately conformable to the marginal contour of the plate portion 70. The retainer 66 lies flat against the forward side of the guide plate 62 and is secured in position thereon by the fastening screws 80 which pass through holes 106 (FIG. 6) formed in the retainer 66.

The retainer 66 may conveniently be described by stating that it is generally of U-shape configuration and is provided with vertically extending side legs 110 (FIG. 3) and a narrow connecting bight portion 112 which extends across the top of the retainer. In the upper region of the retainer 66, and at the level of the bevelled detent recesses 100 in the closure plate 64, a pair of flexible spring detent fingers 114 extend inwardly from. the side legs 100 and normally seat within these recesses. In the lower region of the retainer, and at the level of the bevelled detent recesses 98, a similar pair of flexible spring detent fingers 116 extend inwardly from the side legs 1'10 and normally seat within the latter recesses. The various spring fingers 114 and 116 thus yieldingly bear against the closure plate 64 and serve to maintain the latter in position within the guideways 92.

It is to be noted at this point that the upper region of the assembly 18 as a whole extends upwardly a slight distance into the slot 54 (FIG. 2) in the tool body 14 and is confined therein so that the narrow bight portion 112 of the spring retainer 66 bears against one side of the slot. Normally, the reduced upper edge portion 96 of the closure plate 62 remains slightly spaced from this bight portion 112 as shown in both FIGS. 2 and 4. It should also be observed that the lower region of both the plate portion 70 and spring retainer 66 taper downwardly and inwardly as viewed in FIG. 3 and project below the level of the nose portion 20 of the tool body !14, thus establishing a tool nose proper adapted to be placed against the work when the tool is in use as is customary with conventional tools of the same general character.

Normally, the closure plate 64 seats in the guideways 92 and constitutes a removable front wall for the throat 76. In this position, the spring fingers 114 and 116 on the retainer 66 resist vertical movement of the closure plate and they yieldingly hold the closure plate forwardly against the plate portion 70. If it becomes necessary to remove the closure plate 64 from the assembly 18, it is not necessary to remove the fastening screws 80. By applying downward force to the closure plate, the spring fingers 114 and 116 will ride outwardly upon the bevelled regions 104 of the upper and lower recesses and 98 respectively, thus releasing the detent action of the fingers and allowing the closure plate 64 to he slid endwise downwardly and removed from the assembly 18. Replacement of the closure plate 64 is effected by a reverse procedure and, as the recesses 100 and 93 approach the level of the spring fingers 114 and 116 respectively, the latter will snap into position within the recesses to latch the closure plate in its operative throat-closing position.

Referring now to FIG. 2, in the operation of the stapling implement 12, when the leading staple S in the staple cartridge 32 is moved against the inner side of the closure plate 64 so that the staple enters the throat 76 and becomes aligned with the driver 52, it assumes a position wherein it just clears the upper forward shearing edge 120 (FIGS. 2 and 6) of the shear block 72 so that downward movement of the driver will shear the staple from the cartridge 32 in the usual manner of operation and force the staple downwardly within the throat for penetration of the work. The particular means for positioning the staple S within the throat 76 constitutes no part of the present invention, and magazine arrangements other than the magnetic arrangement illustrated herein may be employed.

If for any reason whatsoever, as for example the failure of the crown portion of a given staple S to clear the shearing edge 120 of the shear block 72, or the encounter by the staple of a hard spot in the work, the staple becomes deformed within the throat 76 as schematically illustrated in FIG. 7, the closure plate 64 will yield bodily since it is held in position within the guideways 92 solely by the upper and lower spring fingers 114 and 116. The closure plate 64 may be said to be floatingly secured in position so that it will yield to the expansive force of a deformed staple, whether the deformation occurs in the upper region, the lower region or a medial region of the throat 76. Upon such yielding of the closure plate 64, the spring fingers 114 and 116 will fiex rearwardly to allow for such rearward displacement of the closure plate 64 and the bevelled areas 104 will afford the necessary clearance region for gradual flexing of the fingers, the fingers tending to lie flat against these bevelled areas when maximum displacement of the closure plate is attained.

The causes of staple jamming in connection with stapling implements of the type under consideration are well known and need but little discussion herein. An exemplary form of staple deformation has been schematically illustrated in FIG. 7 wherein the crown portion of the staple S within the throat 76 has been turned sidewise through an angle of approximately 90 due to failure of the crown portion to fully clear the shearing edge 120 of the shear block 72, and due to the fact that the driver 52, upon engaging the overhanging portion of the staple crown, applied torque to the crown portion tending to rotate it, thus distorting the staple legs as shown. In the illustrated staple distortion of FIG. 7, the driver 52, in its descent in the throat 76 is shown as having carried the thus distorted staple S downwardly in the throat, the closure plate 64 yielding as required to accommodate such downward movement of the staple. Further downward movement of the driver 52 will force the deformed staple S through the nose proper and eject it from the lower end of the throat 76.

Occasionally, the driver 52 will slip past a deformed staple, the closure plate 64 yielding to accommodate the combined width of the deformed staple and the driver. Upon retraction of the driver, the closure plate will partially return to its normal position, thus engaging the deformed staple S. The driver, during the next downward stroke thereof, will shear the next properly positioned staple from the staple cartridge 32 and eject both staples from the throat.

After a potential jam such as has been briefly outlined above has been averted by ejection of the offending staple or staples, the closure plate 64 will be automatically restored by the spring fingers 114 and 116 to its normal position within the opposed guideways 92.

From the above description it will be appreciated that stapling implements employing the present magazine closure and guide assembly 18 of the present invention will be virtually jam-proof and may be operated indefinitely with little attention on the part of the operator. However, if, due to a defective staple cartridge 32, the introduction of a foreign object into the throat 76 from the magazine, or for any other reason whatsoever, a staple deformation of excessive width should cause a jam, then it is a comparatively easy matter to remove the closure plate 64 by manually sliding the same downwardly within the guideways 92 as previously described. To facilitate such manual removal of the closure plate 64, an outstruck lug 122 is formed in the central regions of the plate and is designed for prying engagement with the distal end region of a tool such as the screwdriver shown in dotted lines at T in FIG. 3, the medial region of the tool being designed for engagement with either of the fastening screws 80.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit of the invention. Therefore, only insofar as the invention has particularly been pointed out in the accompanying claims is the same to be limited.

Having thus described the invention, what we claim and desire to secure by Letters Patent is:

1. In a fastener-applying implement, in combination, a magazine defining a chamber for holding a supply of fasteners, a vertical guide plate disposed forwardly of the magazine and having a passage therethrough in communication with the magazine chamber and through which fasteners are successively fed forwardly from the chamber, a driver for said fasteners, the forward side of said guide plate being formed with a vertical forwardly opening channel which intersects said passage, the side walls of the channel being recessed to provide a pair of guideways on opposite sides of the channel, a rigid closure plate slidable vertically in said guideways and normally closing the open side of the channel so as to establish, in combination therewith, a combined throat for receiving the fasteners from said slot and a raceway for the driver, and springs means in sliding engagement with the closure plate and yieldingly urging the latter rearwardly to maintain the same in position within the guideways, said clo sure plate being slidable endwise and vertically in said guideways for removal therefrom and being capable of limited displacement bodily in a forward direction so as to lift the same out of said guideways against the action of said spring means under the influence of internal pressure within the throat occasioned by staple deformation, and detent means releasably maintaining said closure plate in its channel-closing position against vertical sliding movement.

2. In a fastener-applying implement, in combination, a magazine defining a chamber for holding a supply of fasteners, a vertical guide plate disposed forwardly of the magazine and having a passage therethrough in communication with the magazine chamber and through which fasteners are successively fed forwardly from the chamber, a driver for said fasteners, the forward side of said guide plate being formed with a vertical forwardly opening channel which intersects said passage, the side walls of the channel being recessed to provide a pair of opposed guideways on opposite sides of the channel, an elongated rigid closure plate slidable vertically in said guideways and normally closing the open side of the channel so as to establish, in combination therewith, a combined throat for receiving the fasteners from said slot and a raceway for the driver, and a pair of spring fingers effectively secured to the forward side of said wall exteriorly of the magazine and on opposite sides of the closure plate, projecting inwardly over the opposite side edges of the plate, bearing rearwardly at their distal ends against said closure plate, and serving to yieldingly urge the latter rearwardly and maintain the same in position within the guideways, said closure plate being slidable endwise in said guideways for removal therefrom and being capable of limited lateral displacement bodily in a forward direction against the action of said spring fingers under the influence of internal pressure within the throat occasioned by staple deformation.

3. In a fastener-applying implement, in combination, a magazine defining a chamber for holding a supply of fasteners, a vertical guide plate disposed forwardly of the magazine and having a passage therethrough in communication with the magazine chamber and through which fasteners are successively fed from the chamber, a driver for said fasteners, the forward side of said guide plate being formed with a vertical forwardly opening channel which intersects said passage, the side walls of the channel being recessed to provide a pair of opposed guideways on opposite sides of the channel, an elongated rigid closure plate slidable vertically in said guideways and normally closing the open side of the channel so as to establish, in combination therewith, a combined throat for receiving the fasteners from said slot and a raceway for the driver, a first pair of spring fingers adjacent one end of the closure plate, a second pair of spring fingers adjacent the other end of the closure plate, the spring fingers of each pair being effectively secured to the forward side of said wall exteriorly of the magazine and on opposite sides of the closure plate, projecting inwardly over the opposite side edges of the plate, bearing forwardly at their distal ends against said closure plate, and serving to yieldingly urge the latter rearwardly and maintain the same in position within the guideways, said closure plate being slid able endwise in said guideways for removal therefrom and being capable of limited lateral displacement bodily in a forward direction against the action of said spring fingers under the influence of internal pressure within the throat occasioned by staple deformation.

4. In a fastener-applying implement, a magazine closure and guide assembly for closing the front discharge end of a horizontally disposed fastener magazine, providing a throat for guiding fasteners, and a raceway for a driver, said assembly comprising a vertically disposed guide plate adapted to be secured to said discharge end of the magazine transversely thereof and provided with a passage therein through which the fasteners are adapted to pass forwardly, said guide plate being formed with a vertically extending open-sided channel in register with said passage, said channel being provided with side walls which are recessed to provide a pair of opposed guideways on opposite sides of the channel, an elongated rigid closure plate slidable vertically in said guideways and normally closing the open side of the channel so as to establish, in combination with the channel, a combined throat for receiving the fasteners from said passage and a raceway for the driver, a spring retainer in the form of a flat plate secured to the front side of said guide plate and having a plurality of flexible spring fingers overhanging the open side of the channel, bearing slidingly against the closure plate, and yieldingly urging the latter rearwardly to maintain the same in position within said guideways, said closure plate being slidable endwise in said guideways from its normal position for removal from the guideways and also being capable of limited lateral displacement bodily in a forward direction so as to lift the same out of the guideways against the action of said spring fingers and under the influence of internal pressure within the throat occasioned by staple deformation.

5. In a fastener-applying implement, a magazine closure and guide assembly as set forth in claim 4 and including, additionally, a shear block integrally formed on said closure plate, projecting rearwardly from the rear side thereof, and adapted for projection into the magazine through said front discharge end thereof, said shear block being formed with a shearing edge in the vicinity of said passage in the guide plate and designed for shearing cooperation with said driver.

6. In a stapling tool, in combination, a magazine for holding -a supply of staples and having an open front discharge end, a driver for said staples, a guide plate removably secured to said discharge end of the magazine and provided with a U-shaped passage therein through which the staples are adapted to pass forwardly, said guide plate being formed with an open-sided channel in register with said slot, said channel being provided with side walls which are recessed to provide a pair of opposed guideways on opposite sides of the channel, an elongated rigid closure plate slidable endwise in said guideways and normally closing the open side of the channel so as to establish, in combination with the channel, a combined throat for receiving the staples from said slot and a raceway for the driver, a generally U-shape, thin, flat, flexible spring retainer having side legs secured to said guide plate on opposite sides of said channel, each side leg being formed with laterally projecting spring fingers which overhang the open side of the channel and which slidingly bear against said closure plate and yieldingly urge the same rearwardly against the closure plate and maintain the same in position within said guideways, said closure plate being slidable endwise from its normal position in said guideways for removal from the closure plate, and also being capable of limited lateral displacement bodily in a forward direction so as to lift the same out of the guideways against the action of said spring fingers and under the influence of internal pressure within the throat occasioned by staple deformation.

7. In a stapling tool, the combination set forth in claim 6 and wherein said closure plate is formed with a series of detent recesses, one for each spring finger, and in which said spring fingers normally seat for releasably latching said closure plate in its normal position Within said guideways.

8. In a stapling tool, the combination set forth in claim 7 and including, additionally, a shear block integrally formed on said guide plate and projecting into the magazine through said open discharge end thereof, said shear block being formed with lateral side faces in register with the side legs of said U-shaped slot and with a transverse face in register with the crown portion of said slot, the rear edge of said transverse face constituting a shearing edge designed for cooperation with said driver.

9. In a stapling tool, the combination set forth in claim 7 and including, additionally, a fastening screw projecting through each side leg of said generally U-shaped spring retainer and through said guide plate and engageable with the magazine for releasably securing the guide plate and retainer in position, said fastening screws being formed with enlarged heads in clamping engagement with the retainer, and a prying lug formed on said closure plate and projecting forwardly between said side legs of the retainer, said prying lug and enlarged heads constituting reaction points designed for engagement with a prying tool whereby the closure plate may be slid endwise in said guideways for removal purposes.

References Cited by the Examiner UNITED STATES PATENTS 2,801,417 8/1957 Jenny 227-123 2,857,596 10/1958 Allen et al 227-123 2,991,476 7/1961 Seiter 227-123 XR 3,099,012 7/ 1963 Wandel 227123 GRANVILLE Y. CUSTER, JR., Primary Examiner. 

1. IN A FASTENER-APPLYING IMPLEMENT, IN COMBINATION, A MAGAZINE DEFINING A CHAMBER FOR HOLDING A SUPPLY OF FASTENERS, A VERTICAL GUIDE PLATE DISPOSED FORWARDLY OF THE MAGAZINE AND HAVING A PASSAGE THERETHROUGH IN COMMUNICATION WITH THE MAGAZINE CHAMBER AND THROUGH WHICH FASTENERS ARE SUCCESSIVELY FED FORWARDLY FROM THE CHAMBER, A DRIVER FOR SAID FASTENERS, THE FORWARD SIDE OF SAID GUIDE PLATE BEING FORMED WITH A VERTICAL FORWARDLY OPENING CHANNEL WHICH INTERSECTS SAID PASSAGE, THE SIDE WALLS OF THE CHANNEL BEING RECESSED TO PROVIDE A PAIR OF GUIDEWAYS ON OPPOSITE SIDES OF THE CHANNEL, A RIGID CLOSURE PLATE SLIDABLE VERTICALLY IN SAID GUIDEWAYS AND NORMALLY CLOSING THE OPEN SIDE OF THE CHANNEL SO AS TO ESTABLISH, IN COMBINATION THEREWITH, A COMBINED THROAT FOR RECEIVING THE FASTENERS FROM SAID SLOT AND A RACEWAY FOR THE DRIVER, AND SPRINGS MEANS IN SLIDING ENGAGEMENT WITH THE CLOSURE PLATE AND YIELDINGLY URGING THE LATTER REARWARDLY TO MAINTAIN THE SAME IN POSITION WITHIN THE GUIDEWAYS, SAID CLOSURE PLATE BEING SLIDABLE ENDWISE AND VERTICALLY IN SAID GUIDEWAYS FOR REMOVAL THEREFROM AND BEING CAPABLE OF LIMITED DISPLACEMENT BODILY IN A FORWARD DIRECTION SO AS TO LIFT THE SAME OUT OF SAID GUIDEWAYS AGAINST THE ACTION OF SAID SPRING MEANS UNDER THE INFLUENCE OF INTERNAL PRESSURE WITHIN THE THROAT OCCASIONED BY STAPLE DEFORMATION, AND DETENT MEANS RELEASABLY MAINTAINING SAID CLOSURE PLATE IN ITS CHANNEL-CLOSING POSITION AGAINST VERTICAL SLIDING MOVEMENT. 